Review of research on use of radiation-induced mutations in crop breeding in Japan

In Japan, the research on radiation-induced mutation has been conducted as one of the promising methods of plant breeding. Although in the beginning the principal methods used are X-rays and ³²P, we now have various kinds of radiation facilities available for mutation breeding. The fundamental aspects of mutation breeding are investigated at several universities and institutes, and the practical breeding work is carried out by the general organization for crop breeding.Among the characters that have been observed as mutated in rice, chlorophyll deficiency, heading time, culm length and grain-weight are most easily obtained. Some of the induced mutants showed the same or higher productivity as compared to the mother variety. Up to date there are many experiments on the procedural problems associated with radiation-induced mutations in crop breeding. The results of these experiments are reviewed in this paper.     

Insecticidal activity of new fluorinated pyrethroids and their stability toward chemical oxidation and photoreaction

The insecticidal activity of several new fluorinated pyrethroids was measured using houseflies untreated and treated with piperonyl butoxide (PB). 10, 10-Difluorophenothrin and 10, 10-difluoroallethrin, which include fluorine atoms at a position most easily attacked by mixed function oxidases (mfo) in the acid moiety, showed smaller topical LD₅₀ values on the PB-untreated flies than the parent insecticides but rather large values on the PB-treated flies, suggesting that the introduction of fluorine prevents metabolic oxidation, although it has a negative effect on the interaction with a target site. Monofluorinated analogues of phenothrin, in which the structure of chrysanthemic acid was rearranged, still had moderate insecticidal activity, but flies were scarcely killed by 7 fluoroallethrin into which fluorine was introduced at a position most easily oxidized by mfo in the alcohol moiety. Competitive oxidation of the fluorinated derivatives and the parent compounds showed that fluorine at both the 10- and 7′-positions stabilizes the alkenyl side-chains of the pyrethroids against selenium dioxide and m-chloroperoxybenzoic acid. Photochemical studies with 10, 10-difluorophenothrin indicated that the photo-instability of the cyclopropanecarboxylic part could not be improved by this modification.     

Seasonal fluctuations and temperature dependence of leaf gas exchange parameters of co-occurring evergreen and deciduous trees in a temperate broad-leaved forest

Seasonal fluctuations in leaf gas exchange parameters were investigated in three evergreen (Quercus glauca Thunb., Cinnamomum camphora Sieb. and Castanopsis cuspidata Schottky) and one deciduous (Quercus serrata Thunb.) co-occurring, dominant tree species in a temperate broad-leaved forest. Dark respiration rate (Rn), maximum carboxylation rate (Vcmax) and stomatal coefficient (m), the ratio of stomatal conductance to net assimilation rate after adjustment to the vapor pressure deficit and internal carbon dioxide (CO2) concentration, were derived inversely from instantaneous field gas exchange data (one-point method). The normalized values of Rn and Vcmax at the reference temperature of 25 degrees C (Rn25, Vcmax25) and their temperature dependencies (Delta Ha(Rn), Delta Ha(Vcmax)) were analyzed. Parameter Vcmax25 ranged from 24.0-40.3 micromol m(-2) s(-1) and Delta Ha(Vcmax) ranged from 29.1- 67.0 kJ mol(-1). Parameter Rn25 ranged from 0.6-1.4 micromol m(-2) s(-1) and Delta Ha(Rn) ranged from 47.4-95.4 kJ mol(-1). The stomatal coefficient ranged from 7.2-8.2. For the three evergreen trees, a single set of Vcmax25 and Rn25 parameters and temperature dependence curves produced satisfactory estimates of carbon uptake throughout the year, except during the period of simultaneous leaf fall and leaf expansion, which occurs in April and May. In the deciduous oak, declines in Vcmax25 were observed after summer, along with changes in Vcmax25 and Rn25 during the leaf expansion period. In all species, variation in m during periods of leaf expansion and drought should be considered in modeling studies. We conclude that the changes in normalized gas exchange parameters during periods of leaf expansion and drought need to be considered when modeling carbon uptake of evergreen broad-leaved species.     

Enzymatic solubilization of collagen in the skin of diamond squid Thysanoteuthis rhombus: application of a fungal acid protease

Enzymatic solubilization of collagen from the skin tissue of diamond squid Thysanoteuthis rhombus, an underutilized resource in Japan, was attempted using an acid protease from the fungus Rhizopus niveus. This novel approach was compared with the conventional method using porcine pepsin. Both proteases were able to solubilize most of the skin collagen (>90 % of the total collagen) by performing the treatment in 0.5 M acetic acid at 4 °C for 72 h and at an enzyme/substrate ratio (w/w) of 1/10. The SDS-PAGE patterns of the solubilized collagen preparations were quite similar to each other, and two types of collagen (major and minor collagens) were purified from each preparation by cation-exchange column chromatography. These collagen types from the porcine pepsin-solubilized collagen showed similar features to those from the Rhizopus acid protease-solubilized collagen. These results suggest that the Rhizopus acid protease, a protease of non-animal origin, is applicable for solubilizing collagen in the skin of diamond squid.     

Spine-type-specific recruitment of newly synthesized AMPA receptors with learning

The stabilization of long-term memories requires de novo protein synthesis. How can proteins, synthesized in the soma, act on specific synapses that participate in a given memory? We studied the dynamics of newly synthesized AMPA-type glutamate receptors (AMPARs) induced with learning using transgenic mice expressing the GluR1 subunit fused to green fluorescent protein (GFP-GluR1) under control of the c-fos promoter. We found learning-associated recruitment of newly synthesized GFP-GluR1 selectively to mushroom-type spines in adult hippocampal CA1 neurons 24 hours after fear conditioning. Our results are consistent with a "synaptic tagging" model to allow activated synapses to subsequently capture newly synthesized receptor and also demonstrate a critical functional distinction in the mushroom spines with learning.     

Glyphosate Formulations on Nutritional Condition and Productivity of Roundup Ready Soybean

We evaluate the effect of different commercial formulations of glyphosate on the nutritional status of Roundup Ready soybeans (TMG 125). The experiment was conducted under field conditions for two agricultural years. The experimental design used was randomized blocks with four repetitions. The treatments were the implementation of Roundup Original, Trop, Roundup Ultra, Roundup WG, Roundup Transorb R and Zapp QI formulations, all at a dose of 720 g e.a. ha^?1 of glyphosate and two controls (weeding and no weeding). There was no difference in the accumulation of macronutrients. In the second year of evaluation (2011/2012), manganese (Mn) accumulation was affected by the Trop formulations, Roundup Transorb, Zapp QI, Roundup Ultra, Roundup WG. To the accumulation of zinc (Zn), there was a reduction in the application of Trop formulations and Zapp QI. However, this reduction observed did not influence the response of plants in relation to the productive yield.     

Synthetic pyrethroids containing a C–C triple bond

The three commercial synthetic pyrethroids containing a carbon–carbon triple bond, α-ethynyl-2-methylpent-2-enyl (1R)-trans-chrysanthemate, (S)-2-methyl-4-oxo-3-(2-propynyl)cyclopent-2-enyl (1R)-trans,cis-chrysanthemate and [2,5-dioxo-3-(2-propynyl)-1-imidazolidinyl]methyl (1R)-trans-chrysanthemate are reviewed with emphasis on their inventive histories. Their chemistry and efficacy are described briefly. The relationship between stereochemistry and the biological activity is also discussed. © 1998 SCI.     

Purification and characterization of collagenolytic proteases from the hepatopancreas of northern shrimp (Pandalus eous)

Three gelatinolytic proteases (A1, A2, and B) were purified using a synthetic substrate, DNP-Pro-Gln-Gly-Ile-Ala-Gly-Gln-d-Arg, from the hepatopancreas of Northern shrimp (Pandalus eous) by several chromatographic steps involving hydroxyapatite column chromatography, gel filtration on Superdex75, and ion-exchange chromatography on a MonoQ column. Collagenolytic proteases A2 and B, but not protease A1, were demonstrated to digest native porcine type I collagen at 25 degrees C and pH 7.5. Further characterizations of these two collagenolytic proteases showed that the pH optimum of enzyme A2 against DNP-peptide was found to be 11, whereas that of enzyme B was 8.5. The optimum temperature ranged between 40 and 45 degrees C for both enzymes, although enzyme B appeared to be thermally more stable than enzyme A2 at pH 7.5. Both enzymes were strongly inhibited by PMSF and antipain, which suggests that they belong to collagenolytic serine proteases.     

Isolation of antifouling substances from the Palauan sponge Protophlitaspongia aga

ABSTRACT: Fouling organisms cause serious problems by settling on ships' hulls, and other marine infrastructures. Organotin compounds have been developed as effective antifoulants. However, environmental problems are associated with these compounds. It is necessary to find antifouling substances that exhibit a lower toxicity than those substances currently used. A new pyrimidine derivative, 3,4,5,6-tetrahydro-6-hydroxymethyl-3,6-dimethyl-4-pyrimidinecarboxylic acid, (compound 1) and zooanemonin (compound 2) were isolated from the marine sponge Protophlitaspongia aga as antifouling substances against the barnacle Balanus amphitrite . We also found that α-nicotinamide ribose (compound 3) inhibited germination and the attachment of Ulva spores.